Field of the Invention
The present invention relates to session management in network elements having a gateway function in mobile packet core networks, such as GGSN, S-GW and P-GW. In particular, the present invention relates to session termination in such network elements.
The present invention further relates to policy and charging control over Gx interface and SPI and DPI capabilities in GGSN, S-GW and P-GW network elements.
Related Background Art
Prior art which is related to this technical field can e.g. be found in
3GPP TS 23.203 v11.4.0,
3GPP TS 29.212 v11.3.0, and
3GPP TS 29.214 v11.3.0.
The following meanings for the abbreviations used in this specification apply:
AF=application function
APN=access point name
AVP=attribute value pair
BBERF=bearer binding and event reporting function
CAN=connectivity access network
CLI=calling line identification
DL=downlink
DPI=deep packet inspection
DNS=domain name server
GGSN=gateway GPRS support node
GPRS=general packet radio service
IMEI=international mobile station equipment identity
IMSI=international mobile subscriber identity
IP=Internet protocol
MSISDN=mobile subscriber integrated services digital network number
OCS=online charging system
OFCS=offline charging system
P2P=point to point
PCC=policy and charging control
PCEF=policy control enforcement function
PCRF=policy control rule function
PDN=packet data network
P-GW=packet gateway
S-GW=serving gateway
SPI=shallow packet inspection
SPR=subscription profile repository
TDF=traffic detection function
UE=user equipment
UL=uplink
The following problems may occur for a connection between a user equipment (UE) and a mobile packet core network (network).
In case of a network connection outage or congestion, an operator of the network may wish to terminate active sessions which use the problematic network. This way the UE could re-establish the session possibly via another GW or GW node. However, as there is no mechanism for distinguishing between active and inactive sessions, the operator is forced to terminate also inactive sessions.
Further, there may be certain restrictions in the network regarding services or protocols that are allowed to be used. Currently there is a mechanism for restricting the use of such services or protocols (by dropping packets) but that consumes a lot of resources in the GW since UE applications and protocols typically make constant retries that might cause even more UL traffic when services or protocols are restricted. Actually there is no mechanism for automatically terminating those sessions that are using forbidden applications or protocols.
Still further, the operator may wish to force the UE to make a session re-establishment e.g. in order to perform a reconfiguration in the network, e.g. to reconfigure DNS server addresses. Currently there is no mechanism to perform such operation automatically for affected sessions only.
Currently there is no mechanism available that could be used in GGSN/S-GW/P-GW in similar manner for solving the above problems.
If online charging is applied, OCS could terminate the session when the first packet matching a PCC rule requiring termination is detected. This solution, however, has several drawbacks.
That is, the above solution requires extra signaling between PCEF and OCS, and it cannot be used to terminate the session if a change of policy occurs after the first packet matching the PCC rule has been already detected, because then the PCEF will not send any request to the OCS.